Patch by Thiago Macieira <thiago.macieira@nokia.com> on 2010-04-28
Reviewed by Simon Hausmann.

AtomicStringImpl.h:29: error: base `WebCore::StringImpl' with only
non-default constructor in class without a constructor

* wtf/text/AtomicStringImpl.h:
(WebCore::AtomicStringImpl::AtomicStringImpl): Provide a default constructor.
* wtf/text/StringImpl.h: Allow AtomicStringImpl to call a StringImpl constructor through a friend declaration.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@58392 268f45cc-cd09-0410-ab3c-d52691b4dbfc